I don't think it's going to be uniformly helpful to everyone trying to figure out how to improve their site.
I dont either, your not going to experience a dramatic drop, or rise in ranking due to "user metrics" like bounce or exit rates. Does Google use that in their all consuming efforts to figure out the perfect means to rank sites? Probably, but the question is to what degree. (say as opposed to your back link profile which still dominates why you end up where Google places you in the pecking order)
When I see a page with a high bounce rate, the only thing I think about are all those visitors that took off and will never convert for me. From there I try and recognize why people have so little interest in it and then work to improve it.
Bounce rate (and or exit rate I guess but i'm not convinced about that one) is more about monetization of visitors right now than ranking IMHO.